Contact mounting mechanism for electromagnetic relays



Dec. 24, 1963 R. E. LEWIS ETAL CONTACT MOUNTING MECHANISM FOR ELECTROMAGNETIC RELAYS Filed April 24, 1962 United States Patent 3,115,561 C(DNTACT MGUNTHNG MEQHANMM FUR ELEQTRGMAGNETTQ RELAYS Robert Lewis, lirocltton, and Phillip J. Cade, Winchester, Mass, assignors to Electronics Corporation of America, Cambridge, Mme, a corporation of Massachusetts Filed 24, 1962., Ser. No. 189,846 8 (Claims. (tCl. 200-87) This invention relates to electromagnetic relays and more particularly relays of the type in which electric current flowing in a winding connected in a first electrical circuit creates a magnetic force that operates a switch connected in a second electrical circuit.

The principal object of the present invention is to provide an improved electromagnetic relay for use in conjunction with control circuits operating at 120 volts.

A more specific object of the invention is to provide novel and improved electromagnetic relay insulation arrangement capable of economical manufacture which provides electrical separation of electrical circuits controlled by the relay structure well in excess of the minimums 1equired by the Underwriters Laboratories.

In accordance with principles of the invention there is provided an electromagnetic relay which includes a frame structure on which is mounted a pole piece for receiving an electrical coil. A leg of the frame structure is radially spaced from the pole piece and an armature is pivotally mounted on the leg for movement toward and away from the pole piece under the influence of electric current flowing through the coil. The armature has a flat upper surface on which is secured a set of stacked, sheet electrical insulation members which support a movable contact structure for movement with the armature under the influence of the electric current flowing in the coil. A second leg portion of the frame, also radially spaced from the pole piece but on the opposite side thereof from the armature supporting leg, also carries a set of electrical insulation sheets which supports a set of fixed contacts that cooperate with the contacts secured to the armature.

The movable contact insulation set includes a first portion arranged to provide a depressed area which has a horizontal seating surface and a vertical wall adjacent the seating surface. A second portion also includes a depressed area similarly having a horizontal surface and a vertical wall. The two structures are assembled together with the second portion in contact with the armature and secured thereto by an electrical conductive fastening member which engages the horizontal surface of the first portion to secure the two insulator portions in stacked relation and passes through the armature. A second electrically conductive fastening member passes through the first insulator portion at the location of the depressed area of the second portion and secures the movable contact element structure to that first insulation portion. One securing element thus is at the potential of the armature member (ground) and the second securing element is at the potential of the movable conductor members, but they are adequately separated by the configuration of the stacked insulation portions. The arrangement of depressed insulation areas provides adequate insulation thickness and surface leakage paths for meeting standard requirements for operation at voltages of 120 volts and above.

The fixed contact structure is supported from a leg of the frame through the use of insulator sheets and conductive fastening members in related manner. In the preferred embodiment an electrical insulation sheet is secured to the relay frame leg by electrically conductive members which extend through the sheet and the frame. The fixed contacts are mounted in spaced relation in alignment with the movable contacts carried by the armature on a second sheet of electrical insulation. The first sheet is maintained in spaced relation to the second sheet by means of insulation spacers and are secured together by electrically conductive securing elements that extend through both sheets and the spacers. In this arrangement the surfaces between adjacent conductive securing elements of different voltages, are disposed in protected locations so that the possibility of build up of contaminants thereon is minimized. In both the fixed contact assembly and the movable contact assembly in the preferred embodirnent, flat sheets of electrical insulation (formed by stamping operations for example) are secured in stacked relation by rivets. The assembly of relay components and insulation in accordance with the invention provides a sturdy and reliable relay having an economical arrangement of parts easily fabricated by mass production ethods which provides the requisite electrical insulation for the electrical circuit elements.

Other objects, features and advantages of the invention will be seen as the following description of a preferred embodiment thereof progresses in conjunction with the drawing, in which:

FIG. 1 is a side elevational view of the relay structure constructed in accordance with principles of the invention;

FIG. 2 is an end elevational view of the relay structure showing details of the fixed contact structure;

FIG. 3 is a top plan view of the relay structure shown in FIG. 1 showing the relation between the fixed and movable contact structures; and

FIG. 4 is an exploded view of the stacked arrangement of sheet insulation employed in the relay structure shown in FIGS. 1-3.

With reference to FIGS. 1 and 4 the electromagnetic relay structure includes a frame lit which has a pole piece 12 upstanding from the center of the base structure and two upstanding legs 14 and 16 radially positioned with respect to the pole piece 12. A coil ll-8 is seated on the base of the frame surrounding the pole piece 12 and is secured on the pole piece by suitable conventional fastening means as a clamp Ztl.

The upstanding leg 16 includes an outwardly extending lip 22 which receives one end of a coil spring 24, the other end of which is attached to the end 26 of armature plate 23. The spring acts to raise the armature away from the surface of the pole piece 12 positioned as shown in FIG. 1 pivoting on the lower surface of the slot 3i) at the upper end of the leg 16. As in conventional electromagnetic relay operation current in the coil 1% establishes in electromagnetic field flux path through the pole piece, the frame and the armature which acts to pull the armature downward towards the pole piece and into contact therewith against the opposition of the spring .24.

Mounted on the armature are a set of three movable contacts Ell-33, each mounted on the end of a flexible conductive strip 34 that has a horizontal portion 36 and an upstanding terminal portion 35 bent at right angles to the horizontal portion to which a cooperating circuit conductor may be connected. The three movable contact support strips 34- are secured to the armature 23 by means of two sets of flat sheets of phenolic electrical insulation material that are secured together by rivets. The con ductor support strips 34 are secured between a pair of insulator sheets 4-2 and 4d and to a third set 4-6 of greater width than the other two sheets by rivets 48 so that a portion of strip 46 is exposed as a relatively depressed horizontal surface rearwardly of the terminals 38. The insulator sheets and conductor strips are secured together a u in a sturdy unit by the rivets 48 as each of them passes through a contact supporting strip 36 and all three insulator strips, 42, 44 and 46. In addition, as shown in FIG. 3, the rear edge of sheet 42 is relieved to form slots 52 to receive the upstanding terminal portion 33 of the contact support strips so that accurate alignment of each movable contact structure is assured as controlled by a rivet 4S and slot 52.

The second set of insulating strips consists of a relatively narrow sheet 56 and a wider sheet 58 which are stacked on top of the armature with their rear ends aligned with the rear end of sheet 46. These sheets 46, 56 and 58 are secured to the armature 23 by means of rivets 60. The intermediate short sheet 56 provides a recessed area for receiving the rivets 4% which secure in the insulation sandwich of sheets 42, 4e and 46, and the movable contact support strips. Thus the movable contacts are accurately secured to the armature by means of two sets of insulating sheets in an accurate yet economical and easily assembled structure.

In similar manner the upstanding leg 14 of the relay frame has a phenolic insulation sheet '70 secured to it by rivets '72 that are positioned as best indicated in FIG. 2. Spaced from this insulation sheet 76 is a second phenolic insulation sheet '74 maintained at spaced relation by phenolic spacers 76, 75%. Three conductor strips fill support fixed contacts til-83. The upper end 36 of each conductor strip is bent at right angles to the main strip portion to form a fixed contact receiving surface and the lower portion 83 forms a terminal to receive a conductor for connection to circuitry that will be controlled by operation of the relay. Each conductor strip is secured to the insulator sheet 74 by means of two rivets 90. The center strip securing rivets are spaced from the rivets '72 securing sheet 78 to the relay frame both laterally and vertically While the outer conductor strip securing rivets extend through the sheets 70 and 74 and the spacers 76, '78 to secure the insulator sheets in proper spaced relation relative to the relay frame and also maintain the fixed contacts in proper alignment. Thus the fixed contacts of the circuits controlled by the relay are also secured in a simple and inexpensive yet sturdy and reliable manner which permits control of a relay circuit operating at the 120 voltage level.

In this relay, which operates at voltages in excess of 30 volts, the Underwriters requirements specify that there must be at least & of insulation between live circuit parts and at least A over surface distance between such parts. The relay constructed in accordance with principles of the invention employs a novel insulation arrangement which provides insulation in excess of the specified values and which may be manufactured in a rapid and economical manner. Both the movable contacts and the fixed contacts are accurately aligned relative to one another due to the configuration of the supporting insulation members cooperating with the simple securing members.

While a preferred embodiment of the invention has been shown and described modifications thereof will be obvious to those skilled in the art and therefore it is not intended that the invention be limited to the disclosed embodiment or to details thereof and departures may be made therefrom within the spirit and scope of the invention as defined in the claims.

We claim:

1. An electromagnetic relay, comprising in combination, a frame member, a pole piece attached to said frame, a coil surrounding said pole piece member,

said frame member including a first leg radially spaced from said pole piece,

an armature pivotally mounted on said first leg for movement toward said pole piece, under the influence of a magnetic field operated upon energization of said coil,

a movable contact structure arranged to cooperate with if, a fixed contact structure suppo'ted on said frame member,

means to secure said movable contact structure to said armature including a first electrically insulating structure having a recessed area including a horizontal seating surface and a vertical wall adjacent thereto, first electrically conductive fastening means extending through said first insulating structure securing said movable contact structure to the top thereof, a second electrically insulating structure having a reessed area including a horizontal surface and a vertical surface adjacent thereto,

said first and second insulating structures being aligned with one another so that said first electrically conductive fastening means is aligned with said recessed area in said second insulating structure, and second electrically conductive fastening means having a portion seated on the horizontal seating surface of the recessed area of said first electrically insulating structure and extending through said second electrically insulating structure and said armature to secure said movable contact structure to said armature.

2. The electromagnetic relay as claimed in claim 1 wherein said frame member includes a second leg radially spaced from said pole piece, and further including a sheet of electrically insulating material mounted in spaced relation to said second leg,

said fixed contact structure being secured to said electrically insulating sheet and including a contact positioned in the path of movement of said movable contact structure as controlled by said armature and coil for completing an electric circuit.

3. An electromagnetic relay, comprising in combination, a frame member, a pole piece attached to said frame, a coil surrounding said pole piece member.

said frame member including a first leg radially spaced from said pole piece,

an armature pivotally mounted on said first leg for movement toward and away from said pole piece under the influence of a magnetic field created upon energization of said coil,

resilient means for biasing said armature in a direction away from said pole piece,

a movable contact structure including a flexible metal support strip,

a movable contact element secured to one of said support strip and terminal means at the opposite end,

a plurality of electrical insulation sheets arranged in stacked relation for securing said support strip to said armature, said stack of insulation sheets including an armature insulation sheet over-lying and in contact with said armature, a spacer sheet above said armature sheet, upper and lower support strip insulation sheets positioned on either side of said support strip, and a transition sheet member positioned between said spacer sheet and said lower sheet,

first electrically conductive fastening means extending through said upper and lower support strip insulation sheets and said transition sheet member for securing said movable contact support strip thereto,

second electrically conductive fastening means extending through said transition sheet member, said spacer sheet and said armature insulation sheet for securing said stack of insulation sheets to said armature,

a stationary contact structure including a stationary contact element at one end thereof,

and means to secure said stationary contact structure in electrically insulated relation to said frame member with said stationary contact element aligned with said movable contact element so that an electric circuit may be controlled in response to energization of said coil.

4. The electromagnetic relay as claimed in claim 3 wherein one of said support strip insulation sheets includes a configured portion which receives said terminal portion of said contact support strip and said first electrically conductive fastening means extends through said support strip so that said movable contact support strip is secured in accurate alignment by said first electrically conductive fastening means in cooperation with said configured portion of said one sheet.

5. The electromagnetic relay as claimed in claim 3 wherein said stationary contact structure securing means includes a first sheet of electrically insulated material secured to said frame member and a second shet of elec trically insulating material secured in spaced relation to said first sheet,

and electrically conductive fastening means securing said stationary contact structure to said second sheet.

6. An electromagnetic relay, comprising in combination, a frame member, a pole piece attached to said frame, a coil surrounding said pole piece member,

said frame member including first and second upstanding legs radially spaced from said pole piece,

an armature pivotally mounted on said first leg for movement toward and away from said pole piece under the influence of a magnetic field created upon energization of said coil,

resilient means for biasing said armature in a direction away from said pole piece,

a movable contact structure including a plurality of flexible metal support strips,

each said support strip having a movable contact element secured to one end and upstanding terminal means at the opposite end,

a plurality of electrical insulation sheets arranged in stacked relation for securing said support strips to said armature, said stack of insulation sheets including an armature insulation sheet overlying and in contact with said armature, a spacer sheet above said armature insulation sheet, upper and lower support strip insulation sheets positioned on either side of said support strips to align them in a plane with said terminal means protruding above said upper insulation sheet, and a transition sheet member positioned between said spacer sheet and said lower sheet,

a first electrically conductive fastening means corresponding to each support strip extending through said upper and lower support strip insulation sheets, the associated support strip and said transition sheet member for securing said movable contact support strip thereto,

second electrically conductive fastening means spaced from said first electrically conductive fastening means and extending through said transition sheet member, said spacer sheet and said armature insulation sheet for securing said stack of insulation sheets to said armature,

a stationary contact structure corresponding to each said support strip,

each stationary contact structure including a stationary contact element at one end thereof,

and means to secure said stationary contact structures in electrically insulated relation to said second leg of said frame member with said stationary contact elements aligned with said movable contact elements so that electric circuits between said movable and stationary contacts may be controlled in response to energization of said coil.

7. The electromagnetic relay as claimed in claim 6 wherein said stationary contact structure securing means includes a first sheet of electrically insulating material secured by electrically conductive fastening means to said second leg of said frame member and a second sheet of electrically insulating material secured in spaced relation to said first sheet,

and electrically conductive fastening means securing each said stationary contact structure to said second sheet.

8. An electromagnetic relay, comprising in combination, a frame member, a pole piece attached to said frame, a coil surrounding said pole piece member,

said frame member including first and second upstanding legs radially spaced from said pole piece,

an armature pivotally mounted on said first leg for movement toward and away from said pole piece under the influence of a magnetic field created upon energization of said coil,

resilient means for biasing said armature in a direction away from said pole piece,

a movable contact structure including a plurality of flexible metal support strips,

each said support strip having a movable contact element secured to one end and terminal means at the opposite end,

a plurality of electrical insulation sheets arranged in stacked relation for securing said support strips to said armature, said stack of insulation sheets including an armature insulation sheet overlying and in contact with said armature, a spacer sheet above said armature insulation sheet, upper and lower support strip insulation sheets positioned on either side of said support strips to align them in a plane, and a transition sheet member positioned between said spacer sheet and said lower sheet,

first electrically conductive fastening means securing said upper and lower support strip insulation sheets, said support strips and said transition sheet member together as a first unit,

second electrically conductive fastening means securing said transition sheet member, said space-r sheet, said armature insulation sheet and said armature together as a recording unit with a portion of said armature insulation sheet aligned with said first fastening means so that said portion is interposed between said first fastening means and said armature,

said transition sheet linking said two units so that said contact strips are secured to said armature,

a stationary contact structure corresponding to each said support strip,

each stationary contact structure including a stationary contact element at one end thereof,

and means to secure said stationary contact structures in electrically insulated relation to said second leg of said frame member with said stationary contact elements aligned with said movable contact elements so that electric circuits between said movable and stationary contacts may be controlled in response to energization of said coil.

References Cited in the file of this patent UNITED STATES PATENTS 2,798,916 Fisher July 9, 1957 2,896,045 Brunicardi July 21, 1959 2,988,615 Bernier June 13, 1961 3,012,117 Bernier Dec. 5, 1961 3,051,804 Mayer Aug. 28, 1962 

1. AN ELECTROMAGNETIC RELAY, COMPRISING IN COMBINATION, A FRAME MEMBER, A POLE PIECE ATTACHED TO SAID FRAME, A COIL SURROUNDING SAID POLE PIECE MEMBER, SAID FRAME MEMBER INCLUDING A FIRST LEG RADIALLY SPACED FROM SAID POLE PIECE, AN ARMATURE PIVOTALLY MOUNTED ON SAID FIRST LEG FOR MOVEMENT TOWARD SAID POLE PIECE, UNDER THE INFLUENCE OF A MAGNETIC FIELD OPERATED UPON ENERGIZATION OF SAID COIL, A MOVABLE CONTACT STRUCTURE ARRANGED TO COOPERATE WITH A FIXED CONTACT STRUCTURE SUPPORTED ON SAID FRAME MEMBER, MEANS TO SECURE SAID MOVABLE CONTACT STRUCTURE TO SAID ARMATURE INCLUDING A FIRST ELECTRICALLY INSULATING STRUCTURE HAVING A RECESSED AREA INCLUDING A HORIZONTAL SEATING SURFACE AND A VERTICAL WALL ADJACENT THERETO, FIRST ELECTRICALLY CONDUCTIVE FASTENING MEANS EXTENDING THROUGH SAID FIRST INSULATING STRUCTURE SECURING SAID MOVABLE CONTACT STRUCTURE TO THE TOP THEREOF, A SECOND ELECTRICALLY INSULATING STRUCTURE HAVING A RECESSED AREA INCLUDING A HORIZONTAL SURFACE AND A VERTICAL SURFACE ADJACENT THERETO, SAID FIRST AND SECOND INSULATING STRUCTURES BEING ALIGNED WITH ONE ANOTHER SO THAT SAID FIRST ELECTRICALLY CONDUCTIVE FASTENING MEANS IS ALIGNED WITH SAID RECESSED AREA IN SAID SECOND INSULATING STRUCTURE, AND SECOND ELECTRICALLY CONDUCTIVE FASTENING MEANS HAVING A PORTION SEATED ON THE HORIZONTAL SEATING SURFACE OF THE RECESSED AREA OF SAID FIRST ELECTRICALLY INSULATING STRUCTURE AND EXTENDING THROUGH SAID SECOND ELECTRICALLY INSULATING STRUCTURE AND SAID ARMATURE TO SECURE SAID MOVABLE CONTACT STRUCTURE TO SAID ARMATURE. 